Hand operated portable mortising device



C. L. SMITH HAND OPERATED PORTABLE MORTISING DEVICE Aug 15, 1961 2 Sheets-Sheet 1 Filed Oct. 14, 1959 Affor-rrq 5, 1961 c. L. SMITH 2,996,090

HAND OPERATED PORTABLE MORTISING DEVICE Filed Oct. 14, 1959 2 Sheets-Sheet 2 I Q L 5,

Fry. 5'

( INVENTOR. C (par-[e6 L- Smrt'b flt'torrrg I United States Patent Qflice 2,996,090 Patented Aug. 15, 1961 2,996,090 HAND OPERATED PORTABLE MORTISING DEVICE Charles 'L. Smith, 2214 E. Towner "St, Tucson, Ariz. Filed Oct. 14, 1959, Ser. No. 846,439 11 Claims. (Cl. '144-79) My invention relates in general to hand operated tools. It relates more in particular to a hand operated mortising tool driven by rotary means and in which a reciprocating member applies a series of impact blows to the mortising chisel in such manner that the usual guide means is not required.

In the past, mortising operations have been carried out by a stationary type of machine to facilitate applying pressure to guide the mortising chisel. In general, successful mortising machines have been used in wood-working shops and have not been available at building sites. As a consequence it has been necessary either to mortise or otherwise form a special hole or opening in a door frame, door, cabinet or like member before it is delivered to the building site, to provide a construction which does not require a mortising operation, or to so modify hardware that a carpenters drill or carpenters drill plus a hand operated carpenters chisel can be used to shape the wood as required.

The principal object of my invention is the provision of a hand operated mortising tool which can be used directly at a building site.

Another object is to provide a mortising tool which can be operated by the ordinary drill motor usually carried in a oarpenters tool kit.

Still another object of the invention is to provide a mortising tool of the type identified wherein the drill and mortising chisel may be readily changed for adjustment to different sizes of holes.

An additional object of this invention is to provide the combination of a mortise chisel and a mortise drill in which the cutting edges of the mortise drill may be so positioned and so adjusted that while in an idle position these cutting edges of the mortise drill are sufliciently recessed into the cutting end of the mortise chisel to permit portions of the cutting end of the mortise chisel to extend ahead of the mortise drill, thereby permitting the mortise chisel to engage the material to be mortised ahead of the mortise drill, thus adding stability to the mortising operation and also making it possible to enlarge an opening or, if desired, to mortise any portion of a full cut of the mortise chisel.

A further object is the provision of a mortising tool adapted to be driven by rotary power means such as a drill motor, and in which said rotary power means is used directly to drive a mortising drill and simultaneously is converted to reciprocating action driving an impact hammer operating against the shank of the mortising chisel to move same forward in a cutting action as the mortising drill makes a preliminary opening.

Still a further object of the invention is to provide a mortising tool of the type identified, wherein the mortising chisel is spring pressed toward the mortised opening and wherein forward pressure on the tool retracts the mortising chisel against its said spring in proportion to the pressure applied, to thereby control the force of the impact against the shank during a mortising operation.

A final and important object of the invention is the provision of a mortising tool, parts of which may be interchanged with parts of another tool such as a saber saw operated by rotary means such as a drill motor.

Other specific objects and features of the invention will be apparent from a consideration of the following detailed description taken with the accompanying drawings wherein:

FIG. 1 is an exploded view showing a saber saw operable by an electric drill motor and parts of the mortising tool of my invention which may be interchanged with parts of the saber saw to produce the tool of my inventron;

FIG. 2 is an irregular sectional view through the tool housing showing one manner in which rotary motion of the drill motor may be converted to reciprocating action and the driving mechanism for the hammer forming a part of the mortising tool;

FIG. 3 is a futher exploded view showing the mortising chisel, mortising drill and support therefor, and operable parts in close relation therewith;

FIG. 4 is a sectional view showing the principal parts of the mortising tool in the position which they assume when work is not engaged in a mortising operation;

FIG. 5 is a similar sectional view, but showing a position which the parts may assume during a working operation; and

FIG. 6 shows a carpenters chisel which may 'be substituted for the mortising chisel if desired.

In practicing my invention I may produce a mortising tool operated by a drill motor or, as illustrated in the drawings, a tool adapted to have some of its parts interchanged and which, in addition to mortising, may be used for other desired operations. Looking at the drawings, particularly FIGS. 1 and 2, a housing 10 is provided in which a cam shaft 11 is rotatably supported and is driven by a connecting projection 12 which may be received into the chuck 13 of an ordinary drill motor. The cam shaft 11 has a cam slot 14 into which a pin 16 engages, the pin 16 being secured with respect to a traveling block 17 so that rotation of the cam shaft 11 will cause reciprocation .of the traveling block 17. One end of the cam shaft 11 is enlarged and has an end opening 18 into which an adapter 19 may be threaded. Those skilled in the art will recall that in devices of this general type wherein only a saber saw is provided, the cam shaft does not project through the housing 10. In the present case, while it projects through the housing, it is still either flush with or slightly recessed from the exterior end surface of the housing so that this end surface may be engaged directly against the work while being used as a saber saw. The tool may have a usual type of handle 21 which is clasped with one hand, the other hand normally being used to' support the drill motor. When the tool is used as a saber saw, a saber saw member 22 is secured in an exterior slot in the traveling block 17 by Allen screws 23.

For the mortising operations I provide a generally tubular housing member 26 having an integral exterior angular support 27 which is adapted to project into an angular slot 28 in the housing 10, a thumb screw 29 being carried on a contiguous portion of housing 10 for tightening against the angular support 27 to hold the tubular housing 26 in any desired position. Within the tubular housing 26 I provide a special form of chuck member 31 (FIGS. 3 to 5) which receives the shank of the mortising chisel 32, a shoulder 33 on the mortising chisel and a shoulder 34 on the chuck 31 being so positioned and so supporting the mortising chisel that repeated blows against the chuck 31, which also functions as an anvil, will not dislodge or change the position of the mortising chisel. A set screw 36 also may be used to hold the mortising chisel in place.

The chuck 31 is reciprocable within the tubular housing 26 to a lmited extent and for a reason which will be explained. A coil compression spring 37 having one end engaged against a retaining ring 38 and the other rangement it is obvious that normally the mortising:

chisel will be biased entirely forwardly by action of the spring 37, but that it can be forced to the left as shown in FIG. 4- for a reason and in a manner which will be described. Preferably suitable means are provided to prevent relatively rotatory movement between the tubular housing 26 and the chuck 31. Illustratively I show an integral internal projection 35 on the retaining ring 38 riding in an exterior longitudinal slot 30 on the chuck member 31.

A mortising drill 43 extends through the mortising chisel in accordance with usual practice and has its shank engaged in the adapter 19, a set screw 44 being used to hold it in chucked position so that it will be driven by rotation of the adapter 19 which in turn is driven by the cam shaft 11 and in turn by the drill motor. Normally there are lead threads, or at least lead portions of the mortising drill, which project outwardly from the cutting edge of the mortising chisel. While this arrangement can be used in my invention, I prefer to have the mortising drill finish substantially flat across its leading edge so that a hole mortised by means of the tool of my invention normally will have a clean bottom. For best results and ease in operation, the corners or points of the mortise chisel 32 cutting end should extend ahead of the cutting edge of mortise drill 43 when in an idle position as in FIG. 4 so that the tool may be held stable without the necessity of providing a guide.

As a part of the mortising tool I provide a hammer member 46 (FIG. 1) having blade support 47 adapted to be engaged by the block 17 and supported by Allen screws 23 in the same manner that the saber saw is supported in FIG. 1. When so supported with the angular support 27 engaged in the slot 23 of housing 10, the parts assume the positions shown in FIGS. 4 and of the drawings. As shown particularly in FIG. 4, the reciprocation of the block 17 will cause the hammer 46 to move between the solid line position shown in this figure and the dotted line position. Assuming that the mortising chisel has not been caused to engage a work surface as in the mortising operation, the parts may suitably be adjusted so that at this time the hammer 46 in its forward movement will just miss the anvil portion of chuck member 31. However, if the mortising chisel has its forward end engaged against a work surface, the entire assembly comprising the mortising chisel and its chuck 31 will be moved back against the bias of compression spring 37 so that the annular flange 39 will be displaced from the forward, inwardly-projecting flange 41 of the tabular housing 26 a distance determined by the pressure applied. As shown in FIG. 5, only a slight movement of the chuck member 31 has occurred, but this is enough to cause the hammer 46 to engage against the anvil portion and drive the mortising chisel forward. The rotating portion of the tool at the same time will drive the mortising drill so that the mortising chisel will cut the corners as the mortising drill produces its normal circular opening. As greater pressure is applied the action of the hammer 46 is increased and a greater driving action occurs.

In the drawings I have indicated generally that the mortising chisel is square. It is obvious, of course, that the mortising chisel may have any non-circular shape operable to drill a hole other than a round hole in combination with the drill action of a standard type rotating mortising drill. In other words, it should be borne in mind that my invention is not concerned with the specific shape of the mortising drill, it being understood that any of the known shapes can be used if desired.

It is well known that mortising chisels and drills normally come in sets and operate together to produce a desired size and shape of mortised opening. I have found that by using the structure of my present invention I may readily substitute various sizes of drills and chisels by merely loosening the set screws 36 and 44, putting in the new chisel and new drill, and again tightening the set screws. Thus the mortising set of drill and chisel may be used with my invention; using a regular portable drill motor, mortised holes between A1. inch and inch are readily produced, and with slight change in design a still greater range of sizes is easily obtained. Regardless of the size of the mortising chisel and drill, however, I have found that the mortised hole may be drilled at almost any angle, and no special guide means is necessary because there is no pitching or bucking of the tool such as to take it off its course. Since the corners or points of the mortise chisel cutting edge extend ahead of the mortise drill and thus engage the material first to provide stability to the mortising operation, any size hole or opening may be enlarged by any portion of a full cut without changing the mortise chisel and drill to a larger size, also making it possible to mortise an irregularly shaped hole with a regularly shaped chisel.

In addition to the use of either a saber saw or mortising tool with one basic driven mechanism, I may employ any suitable standard type chisel 48 as shown in FIG. 6. In this case the mortising drill is left out completely, and the shank 49 of the chisel is so shaped and designed that it will fit in place of the shank of the mortising chisel and shoulder at two places so that full driving force is imparted to it by the reciprocating block 17 and hammer 46 operating against the anvil portion of the housing member 31. The chisel 48 may be a wood chisel, or it may be used for chiseling stone, concrete, metal, or any other material commonly worked at sites away from factories where machine tools usually are not available. It should be noted also that, while the mortising tool of my invention may be thought to have its greatest utility in shaping wood for cabinets and the like work, it may be employed as well for forming desired suitably shaped holes in concrete, stone, brick or the like, or in fact for operating any type of cutting tool against any work medium where cutting materials are available which will hold their edges under conditions of use.

Those skilled in the art will understand that while I have shown and described my invention as a combination tool in which motion-converting mechanism may operate more than one type of reciprocating member, I may produce the mortising tool of my invention as a separate tool for performing this type of operation only. In this latter case it is obvious, of course, that the design may be simplified somewhat as contrasted with the design necessary when a combination type tool is illustrated. Generally speaking, if the use is one which requires a great deal of mortising type operations, a single purpose tool would be preferred. Such single purpose tool may be designed for drive attachment to the chuck of an ordinary drill motor, or obviously it may be provided with its own motor so that a single purpose unitary complete tool will result. When a tool is desired which would be maintained around the home or even by a carpenter for occasional use, the combination tool as shown may be preferred.

I wish to point out also that while I illustrate and describe the tool of my invention as being driven by a handheld electric motor, any suitable rotating source of power of a portable nature may be used.

While I have described my invention in detail so that those skilled in the art will understand the manner of practicing the same, the scope of my invention is defined by the claims.

I claim:

1. A portable mortising device comprising a housing, a rotatably driven shaft journaled therein, means for connecting said shaft to a means of rotary powar, reciprocating means actuated by said rotary drive shaft, a second housing supported by said first mentioned housing in axial alignment therewith, a chuck member longitudinally reciprocably carried by said second housing adapted to support a mortising chisel, a mortising drill adapted to extend through said mortising chisel, means for connecting said drill to said rotary drive shaft, and a hammer means driven by said reciprocating means and positioned to strike said chuck member so that activation of the rotary drive shaft and resulting reciprocation of said hammer means will simultaneously rotate the mortising drill and cause said reciprocating hammer to strike repeatedly against said chuck member and thereby drive the mortising chisel by a series of hammer-like blows thereon.

2. A portable mortising device comprising a housing having a side slot, a cam shaft journaled in said housing, a block engaging said cam shaft and supported to be longitudinally reciprocated thereby, said block projecting through the said side slot of the housing, a second generally tubular housing releasably supported by said first mentioned housing in axial alignment therewith, a chuck member longitudinally reciprocably carried by said second housing adapted to support a mortising chisel, a mortising drill adapted to extend through said mortising chisel and chuck member for functional engagement by said cam shaft, and a hammer member carried by said reciprocating block and positioned to strike said chuck member so that activation of the cam shaft and resulting reciprocation of the block will simultaneously rotate the mortising drill and cause the said reciprocating hammer to strike repeatedly against said chuck member and drive the mortising chisel by a series of hammer-like blows thereon.

3. A portable mortising device as defined in claim 2, including means to control the impact of said hammer member against the said chuck member.

4. A portable mortising device as defined in claim 2 including a compression spring biasing the mortising chisel chuck member forwardly away from said hammer, whereby by engaging the tool against a work objective the mortising chisel may be displaced against the action of said spring to position the chuck member for more forceful action of the hammer against it and more rapid mortising action.

5. A portable mortising device comprising a mortising drill, means for rotatably connecting said mortising drill to a means of rotary power such as an electric motor, a single piece hollow mortising chisel surrounding portions of said mortising dnill, support means therefor, and reciprocating hammer means actuated by said rotary means of power for applying a succession of hammer like blows to said mortising chisel as said mortising drill is simultaneously rotated.

6. A portable mortising device as defined in claim 5 including means to permit the mortise chisel to retract in its support means, thereby providing means for controlling the force of the hammer like blows against the said mortising chisel.

7. A portable mortising device as defined in claim 5 wherein the said hollow mortising chisel and said mortising drill are so combined to provide means for the cutting edges of the mortising drill to retract and be recessed in the mortising chisel while not in contact with a material surface, to thereby permit portions of the cutting edge of said mortising chisel to extend ahead of said drill and thereby engage the material surface first.

8. A portable mortising device comprising a housing, a drive shaft projecting therethrough, a second housing,

igned with but spaced from said first mentioned housing and attached thereto, said second housing being generally tubular, but having an inturned flange at that end thereof facing away from said first mentioned housing, a tubular chuck member longitudinally slidable Within said second housing and normally projecting therefrom at each end, a mortising chisel supported at one end of said chuck member, the opposite projecting end of said chuck member comprising an anvil, an annular outer projection on said chuck member within the said second housing, a compression spring surrounding the chuck member Within the second housing, a spring retainer ring with said retaining ring and said projection on the chuck member to normally hold the said projection against the flange on the second housing member, a mortising drill within the mortising chisel having its shank connected to said drive shaft, a hammer member longitudinally reciprocably supported between the housings, and means between said hammer and drive shaft for imparting reciprocating movement to the hammer, said spring normally biasing said chuck member and its anvil portion forwardly out of contact with the hammer, whereby during a mortising operation the mortising chisel in contact with a surface is forced backwardly with the chuck member in contact with the hammer to produce a series of sharp blows to drive the mortising chisel forwardly as the hammer reciprocates, and whereby the force of such blows is a function of the pressure of the mortising chisel against the work.

9. A portable mortising device comprising a housing, a drive shaft projecting therethrough for connection at one end to a chuck of a hand operated electrical drill motor, a second housing, aligned with but spaced from said first mentioned housing and attached thereto, said second housing being generally tubular, but having an inturned flange at that end thereof facing away from said first mentioned housing, a tubular chuck member longitudinally slidable within said second housing and normally projecting therefrom at each end, a mortising chisel supported at one end of said chuck member, and the opposite projecting end thereof comprising an anvil, an annular outer projection on said chuck member within the said second housing, a compression spring surrounding the chuck member within the second housing, a spring retainer ring in the second housing, said compression spring being in engagement with said retaining ring and said projection on the chuck member to normally hold the said projection against the flange on the second housing member, a mortising drill within the mortising chisel having its shank connected to said drive shaft, a block longitudinally reciprocably supported in said first mentioned housing, a connection between said block and drive shaft for imparting reciprocable movement to the block in response to rotation of the drive shaft, a hammer member between the housings and surrounding said mortising drill, and a connection between said hammer and reciprocable block for imparting recip rocating movement thereto, said spring normally biasing said chuck member and its anvil portion forwardly out of contact with the hammer, whereby during a mortising operation the mortising chisel in contact with a surface is forced backwardly with the chuck member into contact with the hammer to produce a series of sharp blows to drive the mortising chisel forwardly as the hammer reciprocates, and whereby the force of such blows is a function of the pressure of the mortising chisel against the work.

10. A portable mortising device comprising a housing, a cam shaft rotatable therein, a shaft projecting through one end of said housing adapted for connection to a chuck of a hand operated electrical drill motor, said cam shaft journaled in the opposite end of said housing and provided with means for attachment of an adapter exterior of said housing, an adapter attached to said cam shaft, said adapter having a chuck for receipt of a mortising drill shank, a second housing, aligned with but spaced from said first mentioned housing and attached thereto, said second housing being generally tubular, but having an inturned flange at that end thereof facing away from said first mentioned housing, a tubular chuck member longitudinally slidable within said second housing and normally projecting therefrom at each end, a mortising chisel supported at one end of said chuck member, and the opposite projecting end thereof comprising an anvil, an annular outer projection on said chuck member within the said second housing, a comin the second housing, said spring being in engagement pression spring surrounding the chuck member within the second housing, a spring retainer ring in the second housing, said spring being in engagement with said retaining ring and said projection on the chuck member to normally hold the said projection against the flange on the second housing member, a mortising drill within the mortising chisel having its shank connected to said adapter for rotatable drive from said cam shaft, a block longitudinally reciprocably supported in said first mentioned housing, a connection between said block and cam shaft for imparting reciprocable movement to the block in response to rotation of the cam shaft, a hammer member between the housings and surrounding said mortising drill, and a connection between said hammer and reciprocable block for imparting reciprocating movement thereto, said spring normally biasing said chuck member and its anvil portion forwardly out of contact with the hammer, whereby during a mortising operation the mortising chisel in contact with a surface is forced backwardly with the chuck member in contact with the hammer to produce a series of sharp blows to drive the mortising chisel forwardly as the hammer reciprocates, and whereby the force of such blows is a function of the pressure of the mortising chisel against the work.

11. In a portable mortising device of the character described, a support for a mortising chisel having an anvil, a mortising chisel carried by said support, a mortising drill within said mortising chisel with its shank projecting therefrom, rotary drive means for said mortising drill attachable to said shank, a reciprocably supported hammer near said anvil, means between said drive means and said hammer to impart reciprocable motion thereto, and a compression spring normally biasing said mortising chisel forwardly with said anvil out of contact with the hammer, whereby pressure of the mortising drill against a work piece will produce backward movement of the chisel against the compression spring and place the anvil in the path of the hammer to drive the mortising chisel forwardly in a series of sharp impact blows by the hammer.

References Cited in the file of this patent UNITED STATES PATENTS 468,417 Farmer Feb. 9, 1892 2,436,692 Greene Feb. 24, 1948 2,622,638 Sanders Dec. 23, 1952 2,816,583 Hill Dec. 17, 1957 FOREIGN PATENTS 67,563 Sweden June 25, 1929 

